how does DataMan iPhone App work in the background

The DataMan app on the AppStore (DataMan Lite a free version of the App) helps to Monitor your Data Usage. http://www.iphonelife.com/blog/2686/monitor-your-data-usage-dataman

Can someone p开发者_如何学编程lease elaborate how data usage can be monitored while running in the background.

Actually this kind of applications does nothing in background. As in the apple developers reference, every application goes to suspend mode when the user press the home button (except for some applications like voip or gps-aware or etc.) To monitor data traffic some api functions should be called. These functions return the traffic data statistics even when your application is terminated or in suspend mode. then you may analyze and calculate whatever you want.

For more info: Monitoring network usage excluding local traffic